“The result? Perfect silence everywhere in the concert hall. The trumpeter blows into his instrument, but the sound never leaves the trumpet,” DeMarco said. “That’s exactly the case in our experiment, although we use quantum matter waves instead of sound, and the barriers are created using a speckled green laser beam.”

To simulate electrons moving in waves through a metal, DeMarco’s group uses ultra-cold atoms moving as matter waves in a disordered laser beam. Using laser light as an analogy for a material allows the researchers to completely characterize and control the disorder – a feat impossible in solids, which has made understanding and testing theories of Anderson localization difficult.
The researchers demonstrated that the laser light could completely localize the atoms – the first direct observation of three-dimensional Anderson localization of matter.